SCOTTSDALE, Ariz. — Republican governors gathered Wednesday in this Western city for their annual confab, with the tale of two very different colleagues looming large.

New Jersey’s Chris Christie and Wisconsin’s Scott Walker are, at present, the top-tier prospects among Republican governors for the 2016 presidential race.

Both are fiscal conservatives who have won accolades for breaking the grip of labor unions on their state governments and reining in spending, and both have opposed setting up health care exchanges under Obamacare.

But from there, their paths diverge.

Mr. Christie, who is poised to assume the chairmanship of the Republican Governors Association on Thursday, has struggled to win the hearts of conservative ideologues. His decision to accept Obamacare’s Medicaid expansion in his state, his embrace of President Obama in the aftermath of Superstorm Sandy and his decision last month to call off the state’s legal challenge to a court decision legalizing same-sex marriage in New Jersey all upset movement conservatives.

The whispers of discontent have been so strong on the right that Sen. Rand Paul of Kentucky, another 2016 contender, felt comfortable this week declaring that the New Jersey governor was “not fiscally conservative.” Mr. Christie has felt compelled to publicly restate that he is a true conservative.

But Mr. Christie enjoys a clear advantage on the road to 2016. He just won re-election in a landslide and doesn’t need to focus on another election before the 2016 presidential race. He also will have the mantle of the RGA for the next two years to make the case for his management style and fiscal policies.

Mr. Walker, on the other hand, is skipping this year’s RGA conference as he crisscrosses the country pitching his new book titled “Unintimidated,” which extols his effort to break up Wisconsin’s unions and become the only governor in U.S. history to survive a recall election.

Mr. Walker is embraced by many of the party’s core conservatives and, unlike Mr. Christie, he has rejected Obamacare’s Medicaid expansion and has been cool to the idea of allowing gay marriage in Wisconsin. But he faces a tough re-election battle next year that must be won before he truly can set his sights on 2016.

His book in many ways is designed to be a policy placeholder for the 2016 race until he can finish his re-election business in Wisconsin.

Plenty of other Republicans are likely to jump into the 2016 fray, including Mr. Paul and Sen. Ted Cruz of Texas, who are favorites of the tea party, and former Sen. Rick Santorum of Pennsylvania.

But conventional wisdom has it that Republicans — like Americans in general — prefer to elect as president someone who has the executive experience to competently manage a nation that stretches across five time zones and boasts a population of 317 million.

That conventional wisdom regarding gubernatorial preference is more like an urban myth. Only 17 of the 44 U.S. presidents have been the elected chief executives of their states — though four of the past six presidents — Jimmy Carter, Ronald Reagan, Bill Clinton and George W. Bush — had been governors. So governors for the moment seem to have a bit of an edge, and of the 30 Republican governors in office, Mr. Walker and 21 others are up for re-election — seven of them in states that were friendly to Mr. Obama last year.

The RGA has its share of other popular stars, including retiring Texas Gov. Rick Perry, New Mexico Gov. Susana Martinez and South Carolina Gov. Nikky R. Haley. Each can boast robust state economies and fiscal policies that are working.

But none has the star power of Mr. Christie or Mr. Walker. Both earned their stripes by standing up to their states’ once-powerful public employees unions and winning concessions on collective bargaining and upping employee contributions to benefits packages.

Mr. Christie has run the state attorney general’s office and will have at least six years of experience as governor by the time he starts a presidential nomination drive in 2015, if he does.

Mr. Walker has plenty of managerial experience too, including two four-year terms as Milwaukee County executive — similar to the mayor of a city of nearly 1 million people — and four years as governor. As he works his book tour, he is quick to cite his managerial accomplishments.

“During my eight years as county executive, we cut the number of county workers by 20 percent and turned a $3.5 million county deficit into a surplus,” he said in an interview with The Washington Times.

As governor, he stuck to his promise despite sometimes violent opposition from the unions and their Democratic allies. “I signed a bill that requires public workers to contribute 5.8 percent of their salaries to their pensions — that’s up from zero for most of them — and to pay 12.6 percent of their health insurance premiums, up from 6 percent,” he said.

Mr. Walker takes credit for achieving even more of the things that have been dear to, but unobtainable, by conservatives for years, such as ending collective bargaining for “everything except base wages, ending compulsory union membership, and stopping the forced collection of union dues.”

For many conservatives and independents, his most striking accomplishment was what he described as “freeing school districts from the stranglehold of collective bargaining rules,” thus allowing them, for example, to buy health insurance on the open market and hire and fire teachers based on merit for the first time. Mr. Walker also can boast to having made Wisconsin’s pension system “the only one in the country that is fully funded.”

The RGA meeting will give all the Republican governors a chance to show how their policies are creating economic growth that outpaces most blue states. And they’ll begin to sketch out the policies likely to dominate the agenda in key states for the next few years, ranging from education to tax reform.

The question that looms large and unanswered, however, is whether one of the 28 current GOP executives has the credentials, infrastructure and charisma to be the next president.